This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A380083 #27 May 08 2025 07:12:03 %S A380083 1,6,197,39236,45232349,304285766994,11928254138546089, %T A380083 2725453049877127789064,3629520789795568149638626009, %U A380083 28171611459441395148628640333550174,1274457582507820938168220698796661580252461,336039604487720392926819615640785342048933644491212 %N A380083 a(n) = Pell(n^2)/Pell(n). %F A380083 a(n) = A204327(n)/A000129(n). %F A380083 a(n) = [x^n] x/(1 - A002203(n)*x + (-1)^n*x^2). %p A380083 a:= n-> (f->f(n^2)/f(n))(k->(<<2|1>, <1|0>>^k)[1, 2]): %p A380083 seq(a(n), n=1..12); # _Alois P. Heinz_, May 08 2025 %t A380083 a[n_] := Fibonacci[n^2, 2]/Fibonacci[n, 2]; Array[a, 12] (* _Amiram Eldar_, May 08 2025 *) %o A380083 (PARI) pell(n) = ([2, 1; 1, 0]^n)[2, 1]; %o A380083 a(n) = pell(n^2)/pell(n); %Y A380083 Main diagonal of A383742. %Y A380083 Cf. A000129, A002203, A051294, A204327. %K A380083 nonn,easy %O A380083 1,2 %A A380083 _Seiichi Manyama_, May 08 2025